Preston "Prizzie" Reid explains why he keeps his mix bus light, resisting the urge to stack plugin after plugin in search of extra polish. He used to load it up thinking each plugin added vibe, only to find the final master sounded smaller and less dynamic than the mix.
Overprocessing the mix bus is often a symptom of chasing loudness at the wrong stage. If you're trying to match a reference track's level, that work belongs earlier in the chain, on individual tracks, not stacked at the very end.
Building loudness upstream lets it help you downstream instead of fighting you. Reid applies this directly to the R&B track he's mixing, keeping it laid-back and dynamic on purpose rather than pushing it to compete on loudness.